1. Field of the Invention
The present invention relates to a take-up roller for winding up a continuous sheet-like recording medium while gripping a leading end of the recording medium, and also to a multi-color image recording apparatus using such take-up roller.
2. Description of the Prior Art
In general, when a multi-color image is to be recorded on a recording medium, a latent image formation process and a development process using a liquid developer for each of a plurality of different colors are repeated. In this instance, the recording medium must be moved through an identical image recording station a plurality of times equal in number to the number of colors used in the formation of the multi-color image (i.e., four times when four colors are used). When a rolled continuous sheet of recording paper (hereinafter referred to as "recording paper") is used as a recording medium, a leading end of the recording paper is wound on the take-up roller to securely connect the recording paper with the take-up roller and, thereafter, a succeeding portion of the recording paper is alternately wound on and unwound from the take-up roller each time when an image in one color is recorded on the identical portion of the recording paper. When image recording is completed, the recorded portion of the recording paper is cut off by a knife, for example. The winding of the leading end of the recording paper onto the take-up roller is conventionally performed by a manual operation.
With this manual winding operation, an automatic color image recording process cannot be performed by the conventional color image recording apparatus. Taking this difficulty in account, an attempt has been proposed to automatically wind up the leading end of a continuous recording paper, as disclosed in U.S. Pat. No. 4,733,270. According to the disclosed attempt, a guide plate in the form of a split tube is disposed around a take-up roller for guiding the leading end of the recording paper between a peripheral surface of the take-up roller and an arcuate roll-in guide plate which is disposed adjacent to the peripheral surface of the take-up roller for gripping therebetween the leading end of the recording paper. However, there is no teaching in said U.S. patent as to how the roll-in guide plate operates in gripping the leading end of the recording paper. In addition, the disclosed arrangement of the guide plates cannot rectify or correct the direction of advancement of the recording paper when, due to some reasons, the leading end of the recording paper enters obliquely between the take-up roller and the roll-in guide plate. A subsequent winding operation of the take-up roller necessarily involves the formation of folds or wrinkles on the recording paper.